Production of copies from multicolor screen cinematograph films



v a I I 9% Sept. 1, 1936.

' G. B. HARRISON PRCSDUCTION OP COPIES FROM MULTI COLOR SCREEN'CINEMATOGRAPRFILMS I Filed Feb. 23,- 1935 r 2 Shee' s-Sheet 1 V if LP E T retested Se t 1, 1936- V 3 7 .1'PR0DUCTI0N or" corms FROM Tm'n ooLon sonar; cmsmrooanrnmius #Geo flrey Q Bond Harrison, mord, EngIand 'asl -signor to Ilford Limited, mord Englandfa a Britishcompany' V/ v i .c lpplic ation February 23,1935, Serial No.,':,914

1nGreatBr 'itainMarch1,1934,-; e

zClaims. (cuss-7'5) -jlhis invention relates amethod for making screen copying film ianumber of color copies either positive or negaof color corresponding to the screen color to jtive, for a single master record in-colorasso-g which ,the print is appropriate.-

ciated with a multi-color'screen, either positive It will be .seen that by the above method ,the

.copy very diflerent from the origi l, and p final positive from the separation printsproducing undesirable effects. I g duced by the method illustrated in Figure 1,.

" t is ,an,-;.object oi the present invention .to

copieatrom' a-single mum or,screen ..cinemato-- I of th v aster and positive record and of ,lgraphffllml'inwhich the lackioi definition and I 1 i degradation of one o! the printing steps "reduced or eliminated. L

The invention consists-in the method of pro a 1 each of v termediate color separation prints, and the colors .i n the copies caused by the following examples a ma te master positive or-inegative -'colored cinemato icomprises the steps of preparing from the masnormal master negative and reversing this nega- ..te plurality v.oisets oi color separation tive to give a positive record. This master posh printseach print of a set corresponding to one ti 1 Shown-at in Figures 1 and .From the of the colors of the screen and each being on master'positive a plurality of sets. of threeinter- Iunscreened materialand from each set'preparmediate part-color negative separation print 2 1 ins a p u y f; h 'c p y printing the 3 and 4; each corresponding to one .or the cal -g 55 several prints h Sgt, register in 9 f rat -are:prenared.by contact V i a c r ENT O FICE ducing alarg number ot -coloredcopies irom a positive in natural colors isprepared on three- 7 color screen film -(havingredr green and blue- 5 graph mm f th multircolor screentyve'which moles-screen elements) preferably by taking a using for eachprint light or negative. V detrimental effect of the color screen .oi'the In commercial cinematography it is usual to first copy in the known method described above a make a'large number of positive copies oi the is removed since the color separation prints have originalpr master negative film to be generally no associated color screen. a released for exhibition at various theatres and In carrying out this method the first color sep the like. Since the number of such copies Usuaration prints areprepared with the aid of narally required is exceedingly large and a master row out filters or by means of beams of light copy can only be used satisfactorily to make releach of. color corresponding to one of the colors atively few, say fifty copies, before mechanical of the master screen and from which the wave damage due to repeated passage through the lengths transmitted by the other elements of 15 printing apparatus renders it useless for preparthe .multi-color filter have been eliminated by ing further copies, it is usual to prepare a num-e a process similar to that described in my U. S.

her, say twenty, intermediate copies from the application Serial No. 718,450, filed March 31, e master, which intermediate copies are then used 1934. Owing to the absence of a multi-col or 1 in the preparation of th fin Pu e DY, screen on the copy material the color separay fifty fr ch, thus gi in a thousand fi -c tion prints will each be an accurate reproduction ished copies from a sing e maste eco t ut in monotone of one of the single color elements undue damage thereto. of the master. film, 7 l v In e application 0I this method to the P Some specific methods of carrying the invenin: or as co records on multi-wlor' tionginto effect will nowbe described, by way of screen material, the difliculty arises that if simiexample. and with reference to the accompany- 1 lar screen material'is used for the copy materials, m diagrammatic drawings in h g a certain amount .of lack ofdeilnition and de- Figure 1 u t t one methgd'of producing gradation of color will occur at the first stage t of color separation prints f j or copyin ing to the difficulty of securing Figure -2 illustrates a step in the formation of I curate register 0 ter a p Screensr the mask for use in the method illustrated in l and at the second stage of printing from the in- Figure I, I n

g rmfi py to h fi l PY. 8 further lack Figure 3 "illustrates an alternative method of V of defini n degradatlim of producing'sets of color separation prints.

11pm the same cause. thus rend i h final Figure 4 illustrates one method of printing the 4 rigure 5. shows the registering perforation pmprovide a'f inethod (I -DIQQQFQE large numbers of .i=vide'dnear the end of the base materials of each m 01 the in- 3 a Figure 6 illustrates the engagement of the regdescribed above is Inu h".-=*-istering perforations 0! W0 m y a registerset,

colors of the spectrum are brought to real fociat a plane I and the colors are directed'through themaster positive i on to the sensitive material for the intermediate negative, by a lens 8. Placed in the plane of the spectrum at is'a mask 9 which has opaque portions corresponding in position in the spectrum to the colors which it is desired to eliminate. Thus, in Figure 1A the lower por- 4. To secure registration of the images of the intermediate negatives on the positive copy, the base materials of the negatives and copy are engaged by sprocket wheels in a manner similar to thatused for printing thenegatives.

It is not necessary in printing the negatives negatives (which correspond to the screen eletion of the mask 9 is opaque and serves to eliminate the greens and violets and to pass only those w'avedengths of red which would not be transmitted by the green and violet elements of the master screen. Similarly, in Figure 18 only the central portion of the mask is clear and the top and bottom portions serve to eliminate the green and violet wave-lengths as indicated. In Figure 10 only the bottom portion of the mask'is clear and the red and green wave-lengths are eliminated.

In order to secure accurate registration of the images during the final printing step each of the intermediate negatives is accurately perforated and is fed by means of an accurately formed sprocket in which also engages with the master positive.

One method of producing the masks described ments of the master), should be in register with 'the elements of the screen 'on the copy material.

During the preparation of the final positive irom the original master however, steps should be taken to diffuse the image slightly in order to compensate in some degree for the lack of exact registration between the elements of the original master screen as transferred to the intermediate 'onto the final positive that the elements of the negatives. and the elements of the final copy screen. This diil'usion may be eifected in any of the known ways and may take place either during the preparation of the intermediate records or during the preparation of the final copy a or partly in both stages. In some cases and when suitable separation between the base materials is above is to employ the arrangement shown in Figure 2 in which a beam of parallel light GI and G2 is passed through a filter it having a color transmission similar to that of the elements of one color of the master positive and the light transmitted by this filter is. analyzed into a spectrum by means of a prism and lens similar to those employed in the printing step. as described above. A color-sensitive photographic plate It is inserted in the plane of the spectrum and it will be seen that after exposure to this spectrum and development. the mask will bear an opaque band, corresponding in position in the spectrum to light passed by the elements of one color of the :master screen. The process is repeated using a filter ll corresponding to a dif-' ferent color of the, master screen producing a second mask which may be combined with the first to provide a mask. which when employed in the manner shown in Figure 1, will allow to pass light of wave-lengths corresponding to one of the colors of the master screen. but' will-not-aliow screen.

either of the other colors of the screen or'wavearranged sufiicientdiifusion may be provided-by the fact that in the method described above the light of each color is 'notparallel at the printing printing light is shown in Figure 3. In this case 7 l a sharp cut filter I is inserted in the path of a parallel beam of light GI and G2 used for printing. The filter I has atransmission such that only light corresponding to one of the colors of the master screen is allowed to pass, and light which would be transmitted by any of the other screen elements is absorbed. In Figure 3 the printing of only one of the intermediate negatives is shown. but it is to be understood that the length which are common to any two colors of the masks and combining them, a single mask may be produced by successively exposing a plate with diiferent filters H in position and then developing the plate. A number of sets of negative. part-color separation prints are prepared as described above from each master and for each positivethe negatives from one set i-are successively printed in Alternatively, instead of exposing two register onto positive three color screen material it as shown in Figure 4." The light used for printing each. of the negatives is similar to that used for the making of that negative. and -is obtained in similar manner, as shown in Figure same arrangement is employed for each of the intermediate negatives; using appropriate filters.

The printing of the final po'itive from the intermediate negatives is carried out in similar manner using the same or similar filters in each case.

.In order to ensure that all the part-color in-.

, from the master on to an intermediate negative or from an intermediate negative on to a final positive, the registering perforations of each film are engaged by a spring pressed plunger ll asshown in Figure 6 and the films are engaged by the driving sprocket wheel while their correct relative positions are thus determined. Theplunger i8 is released from engagement with the films before feeding is commenced.

,.Iclaim:

1. Themethod of producing a large number of colored copies from a master positive or negative colored cinematographfilm of the .multi-color screen type which comprises the steps of preparing irom the master film a plurality of sets'of color separation prints each print of a set corresponding to one of the colors of the screen and each being on unscreened material, the light used for printing each print being of color corresponding to one of the colors of the master screen but having eliminated substantially all light of wavelengths which'wouid be transmitted by elements or the screen "of diflerent color and from each set preparing a plurality'oi' finished copies by print- .I r I.

color screen copyingvfilm using for each print light of color corresponding to the screen color to which the print is appropriate but having eliminatedvsubstantialiy all light of wave-lengthswhich would be transmitted-by elements oi'the screen of different color.

2. The method of producing a large nnmber of 1 colored copies from a master positive or negative colored cinematograph film oi the vmulti-color screen type which compnsesthe steps of preparing from the master him a plurality of setsof color separation prints each print of a set corresponding to one of the colors of the screenand each-being on unscreened material, the light used ing to one 01' the colors 0! the master screen but having eliminated substantially all light of wave lengths which would be transmitted by elements of the'screen of different color, from each set preparing a plurality of finished copies by printing the several prints of the set in register on to color screen copying film vusing for each print for printing each print being ofcolor correspond light of color corresponding to the screen color to which the print is appropriate but having eliminated substantially, all light of .wave-lengths printing steps diilusing the image slightly.

GEOFFREY nomnmnmsonf '15 j which would be transmitted by elementsoi the 1 screen of diflerentcolor and during one of the 

